Self-reaming rock drill coupling



p H, 19%? H. M. BINKLEY 3,

SELF-REAMING ROCK DRILL COUPLING Filed June 15, 1964 INVENTOR. HOWARD M. BlN KLEY ORNEYS United States Patent Office 3,313,3fi4 Patented Apr. 11, 1967 3,313,364 SELF-REAMENG ROCK DRHL COUPLING Howard M. llinkley, Red River, N. Mex. 87558 Filed June 15, 1964, Ser. No. 375,077 4 Claims. (Cl. 175-325) This invention relates to rock driiling apparatus and, more particularly, to the couplings employed between sectionalized drill rods or rods and shanks.

Rock drilling is seldom performed with a one-piecebit, but instead, by sectionalized drill rods, shanks, couplings and bits. The rods are hollow having an axial bore therethrough into which are fed drilling fluids that cool the bit and wash away the cuttings. Both ends of the rod sections are most often threaded, the forward end to receive the internally-threaded bit and the rear end to screw into a hollow tubular coupling. This coupling is used to fasten together two or more sections of drill rod or to interconnect the rearmost rod section to the shank which fits into the drill itself.

The prior art drill rod couplings are, for the most part, nothing more than short tubular sections of alloy steel that is either heat-treated or Carburized to resist wear and withstand the substantial impact loads impresse thereon by the drill so as to transmit this motion most efiiciently to the bit.

The outside diameter of the coupling is usually somewhat less than the drilled hole produced by the bit but, nevertheless, it is not uncommon to have the drills stick in the hole due to the cuttings becoming compacted around the rod, particularly, the coupling. When this occurs it is difficult, and sometimes impossible, to free the bit which may have to be abandoned in the face being drilled. In any event, freeing a frozen drill rod string is an expensive and time-consuming operation that should be avoided if it is possible to do so.

It has now been found in accordance with the teaching of the present invention that many instances of stuck drill strings brought about by compacted cuttings and even crooked bores can be eliminated by the simple, but unobvious, expedient of providing the coupling with cutting teeth of its own which function to break up or otherwise cut through the obstruction. In the preferred embodiment of the invention, a plurality of equi-angularly spaced generally V-shaped teeth protrude from both the front and rear exposed ends of the coupling in position to engage the cuttings that become impacted between the drill rod surfaces and the bored hole.

Accordingly, it is the principal object of the present invention to provide a novel and improved drill rod coupling for rock drill strings.

A second objective is the provision of a self-cleaning coupling of the type above-mentioned.

Another object of the invention is to provide a rock drill coupling equipped with cutting teeth adapted to ream the bore and, if necessary, cut itself free should it become jammed in a crooked hole.

Still another objective is the provision of a device of the character aforementioned that requires no alteration of existing rods and shanks to accommodate same, it being adaptable for use with substantially all types and styles of rock drilling equipment.

An additional object of the invention herein disclosed and claimed is the provision of a rock drill coupling that is very little, if any, more expensive to manufacture than the conventional couplings having no reaming teeth.

Further objects are to provide a coupling that is simple, versatile, rugged, lightweight, easy to use,'compact and even decorative.

Other objects will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawings that follows, and in which:

FIGURE 1 is a side elevation showing the improved coupling of the present invention in place connecting a drill rod having a removable bit at one extremity to the drill shank;

FIGURE 2 is an enlarged elevation of the coupling itself, portions of the wall having been broken away and shown in section to reveal the interior construction; and

FIGURE 3 is an end view revealing the tooth shape and placement around the periphery of each end.

Referring now to the drawings for a detailed description of the invention and, initially, to FIGURE 1 for this purpose, reference numeral 1% represents a rock drill bit of conventional design detachably connected to one extremity of a drill rod section 12 that is, in turn, screwed into the internally-threaded hollow interior of the coupling that has been broadly designated by reference numeral 14. Similarly threaded into the other extremity of the coupling 14 is a drill shank 15, likewise of standard design. Of course, in longer drill strings, more than one drill rod section 12 would be interposed between the bit 10 and shank 15 with couplings 14 forming the connector at each juncture. The internal construction of the coupling which forms no part of the present invention is such that the adjacent ends of the rod and shank abut one another at about the coupling midpoint so as to transmit the impact force of the drill to the bit.

Next, with reference to all three figures of the drawing, it will be seen that the coupling 14 is cylindrical so as to present an outer surface of uniform diameter somewhat smaller than the hole that Will be bored by bit Iii. On the other hand, the external diameter of the coupling is larger than that of either the shank or drill rod so as to expose the coupling ends 16 even when used with those shanks and rods (not shown) which have sections of increased cross-section spaced away from the threads.

The significant improvement in the coupling 14 is the addition of a plurality of teeth 18 on the ends 16 projecting axially therefrom in both directions and in position to engage any cuttings that may become compacted around the rod or shank in the annular space left between these elements and the bored hole. As shown, each end 16 of the coupling includes four equi-angularly-spaced teeth 18 although, obviously, a lesser or greater number could be used having different angular spacings.

The tooth design is significant because the generally V-shaped configuration shown has proven to be advantageous in breaking up compacted cuttings. The rapid reciprocating action of the rock drill as contrasted with the smooth unidirectional rotary motion of other types of drills makes the V-shaped tooth especially desirable. The obtuse angles a and 1) (FIGURE 2) produced at the base of each tooth prevent clogging while the acute angle 0 at their vertex bites quickly and easily into either the rock formation or compacted cutting lying adjacent either end thereof. Also, the fact that the teeth lie wholly inside the cylindrical surface of the coupling body 20 leaves the assembly free to reciprocate and free itself which can become a problem with teeth having radial projections although the latter can, of course, be used. On the other hand, in formations where straight bore are difiicult to come by and the drill string is more likely to jam because of a crooked hole than compacted cuttings, it is desirable to have radially-projecting teeth that will bite into the undisturbed formation and enlarge the bore until the assembly frees itself. For this purpose, a combination tooth 22 like that shown on the bit 10 in FIGURE 1 can be substituted for the teeth 18 on the coupling. Teeth 22 have both an axially-facing cutting edge 24 and a radial cutting edge 26.

The teeth can be formed integral with the coupling as shown in FIGURE 2 in which case they would be of alloy steel suitably case hardened or otherwise treated to give the proper wearing qualities. If necessary, the teeth can be Carballoy inserts such as the teeth 22 on the drill bit 10 although the additional expense of such teeth and the increased cost of manufacture of such a coupling are seldom justified or needed in a unit specifically designed for occasional use in freeing the drill string as contrasted with the continuous functional use of the bit teeth. For this same reason, the combination tooth design 22. is seldom necessary on the coupling and the cost of manufacturing same is obviously greater due to their more complex design.

Having thus described the several useful and novel features of the improved drill rod coupling of the present invention, it Will be apparent that the many worthwhile objectives for which it was designed have been achieved. Although but a few possible embodiments of the invention have been illustrated and described herein, I realize that certain changes and further modification may well occur to those skilled in the art within the broad teaching hereof; hence, it is my intention that the scope of protection afforded hereby shall be limited only insofar as such limitations are expressly set forth in the appended claims.

What is claimed is:

1. The improved coupling for detachably interconnecting rock drill rod sections together in axially-aligned endto-end relation which comprises: a hollow cylindrical metal body having an axial bore therethrough shaped to releasably retain the end portions of a pair of drill rod sections inserted into opposite extremities thereof, said body terminating at opposite ends in spaced substantially parallel surfaces normal to the bore axis, and axially protruding teeth projecting from both end surfaces of the body, said teeth having their outside surfaces located wholly Within the external cylindrical surface of the body and their inside surfaces positioned to lie wholly outside the surface of the drill rod section fastened into the adjacent end of the axial bore.

2. The improved rock drill coupling as set forth in claim 1 in which the outside surfaces of the teeth form continuations of the cylindrical body surface.

3. The improved rock drill coupling as set forth in claim 1 in which the teeth are essentially V-shaped.

4. The improved rock drill coupling as set forth in claim 1 in which both ends are provided With at least two teeth arranged in equi-angularly spaced relation to one another leaving a fiat planar surface therebetween.

References Cited by the Examiner UNITED STATES PATENTS 1,045,954 12/1912 Decker 175401 1,848,762 3/1932 Atkinson 175-401 2,234,451 3/1941 Ransome 175401 2,904,312 9/1959 Schneider 175-401 3,094,180 6/1963 Heith 175401 3,145,789 7/1964 LaWry 175-401 CHARLES E. OCONNELL, Primary Examiner.

JAMES A. LEPPINK, Examiner. 

1. THE IMPROVED COUPLING FOR DETACHABLY INTERCONNECTING ROCK DRILL ROD SECTIONS TOGETHER IN AXIALLY-ALIGNED ENDTO-END RELATION WHICH COMPRISES: A HOLLOW CYLINDRICAL METAL BODY HAVING AN AXIAL BORE THERETHROUGH SHAPED TO RELEASABLY RETAIN THE END PORTIONS OF A PAIR OF DRILL ROD SECTIONS INSERTED INTO OPPOSITE EXTREMITIES THEREOF, SAID BODY TERMINATING AT OPPOSITE ENDS IN SPACED SUBSTANTIALLY PARALLEL SURFACES NORMAL TO THE BORE AXIS, AND AXIALLY PROTRUDING TEETH PROJECTING FROM BOTH END SURFACES OF THE BODY, SAID TEETH HAVING THEIR OUTSIDE SURFACES LOCATED WHOLLY WITHIN THE EXTERNAL CYLINDRICAL SURFACE OF THE BODY AND THEIR INSIDE SURFACES POSITIONED TO LIE WHOLLY OUTSIDE THE SURFACE OF THE DRILL ROD SECTION FASTENED INTO THE ADJACENT END OF THE AXIAL BORE. 